Many automotive seat headrest assemblies are known to the art in which a headrest body is pivotally mounted to a mounting post for connection to a vehicle seat and provided with a ratcheting pivot adjustment device for permitting the headrest body to rotate forwardly with respect to the mounting post while locking the headrest body against rearward rotation. Locking the headrest body against rearward rotation allows the headrest body to act as a barrier for an occupant's head in the event the vehicle in which the seat is mounted is involved in a rearend collision.
The headrest ratcheting devices known to the art are typically located within the headrest body adjacent one or the other side edges of the headrest body. Such placement, however, is deficient since the ratcheting device is out of the direct line of force applied centrally to the headrest body by the occupant's head, thereby subjecting the ratcheting device to undesirable torsion loads. An example of such a headrest assembly is disclosed in the U.S. Pat. No. 4,674,797 to Tateyama, granted Jun. 23, 1987.
The U.S. Pat. No. 4,640,549 to Yokota, granted Feb. 3, 1987 teaches providing a ratcheting mechanism on each side of the headrest body which would solve the torsional loading problem. However, providing two ratcheting mechanisms adds unnecessarily to the cost and complexity of manufacturing a pivotal headrest assembly.